Multi-Band Low-Profile Non-Uniform Metasurface Antenna for Sub-6-GHz Applications

This paper presents the design of a compact nonuniform metasurface antenna with dimensions of 70×70 mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>. The antenna basically comprises a 1.6 mm-thick metasurface patch and a 1 mm-thick substrate, separated by a 5-mm air gap to enhance performance. The proposed design is analyzed using CST Microwave Studio, evaluating key parameters such as Voltage Standing Wave Ratio (VSWR), |S11|, and radiation efficiency. Simulation results indicate excellent impedance matching, with |S11| below −10 dB across 2.35 GHz to 6 GHz, reaching a minimum of −36.647 dB at 5.16 GHz. The VSWR remains below 2.5, with a minimum of 1.5 at 5.16 GHz. Additionally, the antenna demonstrates high radiation efficiency, ranging 74% to 80.7%, indicating effective energy radiation. The experiment results highlight the potential of the proposed non-uniform metasurface antenna for next-generation wireless communication systems, especially for 5G and beyond, where compact size, broad bandwidth, and high efficiency are essential. Notably, the integration of a non-uniform metasurface geometry and strategically placed air gap enhances overall performance, making it a promising candidate for future wireless technologies.